Liquid crystal devices and OLEDs (i.e., organic light-emitting diodes) display device are two common types of display devices. In the display device, each of basic display units, which can display various colors, namely pixel dots (also refers to pixels or pixel units), is implemented by a plurality of sub-pixels displaying primary colors, light of the primary colors emitted by the sub-pixels can be mixed with each other to obtain different colors. For example, each pixel unit can comprise one red sub-pixel, one green sub-pixel and one blue sub-pixel, and such mode is called an RGB mode. For example, each pixel unit can comprise one red sub-pixel, one green sub-pixel, one blue sub-pixel and one white sub-pixel, and such mode is called an RGBW mode.